Liquid-crystalline media, components for high-frequency technology, and mesogenic compounds

ABSTRACT

The present invention relates to a liquid-crystal medium which comprises a component A which consists of one or more compounds of the formula I 
     
       
         
         
             
             
         
       
     
     in which the parameters have the respective meanings given in the claims or in the text, and to the corresponding, novel mesogenic compounds and to the preparation thereof. The present invention likewise relates to the use of these liquid-crystal media, in particular in components for high-frequency technology, and to components of this type which contain media according to the invention, and to the production and use of these components. The components according to the invention are suitable, in particular, as phase shifters in the microwave and millimetre wave region, for microwave and millimetre wave array antennae and very particularly for so-called tuneable “reflectarrays”.

AREA OF THE INVENTION

The present invention relates to liquid-crystalline media, in particularfor high-frequency technology, especially components for high-frequencydevices, in particular antennas, especially for the gigahertz region andthe terahertz region, which are operated in the microwave or millimetrewave region. These components use particular liquid-crystalline,chemical compounds or liquid-crystalline media composed thereof for, forexample, the phase shifting of microwaves for tuneable phased-arrayantennas or for tuneable cells of microwave antennas based on“reflectarrays”. In addition, the present invention relates to novelmesogenic compounds.

PRIOR ART AND PROBLEM TO BE SOLVED

Liquid-crystalline media have long been utilised in electro-opticaldisplays (liquid crystal displays—LCDs) in order to display information.

Bistolan compounds, also known as triphenyldiacetylenes, having anadditional alkyl substitution on the central phenylene ring areadequately known to the person skilled in the art.

For example, Wu, S.-T., Hsu, C.-S, and Shyu, K.-F., Appl. Phys. Lett.,74 (3), (1999), pages 344-346, discloses various liquid-crystallinebistolan compounds containing a lateral methyl group, of the formula

Besides liquid-crystalline bistolan compounds of this type containing alateral methyl group, Hsu, C. S., Shyu, K. F., Chuang, Y. Y. and Wu,S.-T., Liq. Cryst., 27 (2), (2000), pages 283-287, also disclosescorresponding compounds containing a lateral ethyl group and proposesthe use thereof, inter alia, in liquid crystal optically phased arrays.

Dabrowski, R., Kula, P., Gauza, S., Dziadiszek, J., Urban, S, and Wu,S.-T., IDRC 08, (2008), pages 35-38, mentions dielectrically neutralbistolan compounds with and without a lateral methyl group on thecentral ring besides the strongly dielectrically positiveisothiocyanatobistolan compounds of the formula

Compounds containing three C—C triple bonds, such as, for example, thecompound

are mentioned in JP 2003-207631 A) and are proposed for use in opticalfilms, polarisers and in liquid crystals of the light-scattering type.

However, liquid-crystalline media have recently also been proposed foruse in components for microwave technology, as described, for example,in DE 10 2004 029 429 A and in JP 2005-120208 (A).

An industrially valuable application of liquid-crystalline media inhigh-frequency technology is based on their property that theirdielectric properties can be controlled, particularly for the gigahertzregion and the terahertz region, by a variable voltage. This enables theconstruction of tuneable antennas which contain no moving parts(Gaebler, A., Moessinger, A., Goelden, F., et al., “LiquidCrystal-Reconfigurable Antenna Concepts for Space Applications atMicrowave and Millimeter Waves”, International Journal of Antennas andPropagation, Volume 2009, Article ID 876989, (2009), pages 1-7, DOI:10.1155/2009/876989).

Penirschke, A., Müller, S., Scheele, P., Weil, C., Wittek, M., Hock, C.and Jakoby, R.: “Cavity Perturbation Method for Characterisation ofLiquid Crystals up to 35 GHz”, 34^(th) European MicrowaveConference—Amsterdam, pp. 545-548, describe, inter alia, the propertiesof the known single liquid-crystalline substance K15 (also called4-n-pentyl-4′-cyanobiphenyl or PP-5-N, Merck KGaA, Germany) at afrequency of 9 GHz.

DE 10 2004 029 429 A describes the use of liquid-crystal media inmicrowave technology, inter alia in phase shifters. DE 10 2004 029 429 Ahas already investigated liquid-crystalline media with respect to theirproperties in the corresponding frequency range.

For use in high-frequency technology, liquid-crystalline media havingparticular, hitherto rather unusual, unconventional properties, orcombinations of properties, are required.

A. Gaebler, F. Goelden, S. Müller, A. Penirschke and R. Jakoby “DirectSimulation of Material Permittivites using an Eigen-SusceptibilityFormulation of the Vector Variational Approach”, 12MTC2009—International Instrumentation and Measurement TechnologyConference, Singapore, 2009 (IEEE), pp. 463-467, describe thecorresponding properties of the known liquid-crystal mixture E7(likewise Merck KGaA, Germany).

DE 10 2004 029 429 A describes the use of liquid-crystal media inmicrowave technology, inter alia in phase shifters. DE 10 2004 029 429 Ahas already investigated liquid-crystalline media with respect to theirproperties in the corresponding frequency range. In addition, itmentions liquid-crystalline media which comprise compounds of theformulae

besides compounds of the formulae

Liquid-crystal media which comprise, for example, compounds of theformula

are proposed for use in components for high-frequency technology, forexample, in

A. Lapanik, “Single compounds and mixtures for microwave applications,Dielectric, microwave studies on selected systems”, dissertation,Technical University of Darmstadt, 2009, (D17),

A. Lapanik, F. Golden, S. Müller, A. Penirschke, R. Jakoby and W. Haase,Frequenz, in print,

“Highly birefringent nematic mixtures at room temperature for microwaveapplications”, A. Lapanik, F. Golden, S. Müller, R. Jakoby and W. Haase,Journal of Optical Engineering, submitted for publication, and in thefollowing, hitherto unpublished patent applications: DE 10 2009 051892.4, DE 10 2010 025 572.6, DE 10 2010 045 370.6 and DE 10 2010 051508.0.

However, the compositions known to date are afflicted with seriousdisadvantages. Besides other deficiencies, most of them result indisadvantageously high losses and/or inadequate phase shift orinadequate material quality (η).

Novel liquid-crystalline media having improved properties are thusnecessary. In particular, the loss in the microwave region and/ormillimetre wave region must be reduced and the material qualityimproved.

In addition, there is a demand for an improvement in the low-temperaturebehaviour of the liquid-crystalline media and thus also of thecomponents. Both an improvement in the operating properties and also inthe shelf life are necessary here.

Thus, there is a considerable demand for liquid-crystalline media havingsuitable properties for corresponding practical applications.

PRESENT INVENTION

Surprisingly, it has now been found that it is possible to achievecomponents for high-frequency technology which do not have thedisadvantages of the prior-art materials, or at least only do so to aconsiderably reduced extent, if selected liquid-crystalline media areemployed.

The present invention thus relates to liquid-crystalline media whichcomprise one or more compounds of the formula I,

in which

denotes

preferably

particularly preferably

-   L¹ denotes alkyl having 1 to 6 C atoms, cycloalkyl having 3 to 6 C    atoms or cycloalkenyl having 4 to 6 C atoms, preferably CH₃, C₂H₅,    n-C₃H₇ (—(CH₂)₂CH₃), i-C₃H₇ (—CH(CH₃)₂), cyclopropyl, cyclobutyl,    cyclohexyl, cyclopent-1-enyl or cyclohex-1-enyl, and particularly    preferably CH₃, C₂H₅, cyclopropyl or cyclobutyl,-   X¹ denotes H, alkyl having 1 to 3 C atoms or halogen, preferably H,    F or Cl, and particularly preferably H or F and very particularly    preferably F,-   R¹¹ to R¹⁴, independently of one another, denote unfluorinated alkyl    or unfluorinated alkoxy, each having 1 to 15 C atoms, unfluorinated    alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl, each    having 2 to 15 C atoms, or cycloalkyl, alkylcycloalkyl,    cycloalkenyl, alkylcycloalkenyl, alkylcycloalkylalkyl or    alkylcycloalkenylalkyl, each having up to 15 C atoms, and    alternatively one of R¹³ and R¹⁴ or both also denote H,-   preferably R¹¹ and R¹², independently of one another, denote    unfluorinated alkyl or unfluorinated alkoxy, each having 1 to 7 C    atoms, or unfluorinated alkenyl, unfluorinated alkenyloxy or    unfluorinated alkoxyalkyl, each having 2 to 7 C atoms,-   particularly preferably R¹¹ denotes unfluorinated alkyl having 1 to    7 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or    unfluorinated alkoxyalkyl, each having 2 to 7 C atoms, and-   particularly preferably R¹² denotes unfluorinated alkyl or    unfluorinated alkoxy, each having 1 to 7 C atoms, and-   preferably R¹³ and R¹⁴ denote H, unfluorinated alkyl having 1 to 5 C    atoms, unfluorinated cycloalkyl or cycloalkenyl having 3 to 7 C    atoms, unfluorinated alkylcyclohexyl or unfluorinated    cyclohexylalkyl, each having 4 to 12 C atoms, or unfluorinated    alkylcyclohexylalkyl having 5 to 15 C atoms, particularly preferably    cyclopropyl, cyclobutyl or cyclohexyl, and very particularly    preferably at least one of R¹³ and R¹⁴ denotes n-alkyl, particularly    preferably methyl, ethyl or n-propyl, and the other denotes H or    n-alkyl, particularly preferably H, methyl, ethyl or n-propyl.

The liquid-crystal media according to the invention are eminentlysuitable for use in components for high-frequency technology or for themicrowave region and/or millimetre wave region of the electromagneticspectrum. The present invention relates to this use of the media and tothese components.

In a first preferred embodiment of the present invention, the componentfor high-frequency technology contains a liquid-crystal medium whichcomprises a component A which consists of one, two or more compounds ofthe formula I.

In accordance with a further preferred embodiment of the presentinvention, the component for high-frequency technology contains aliquid-crystalline medium comprising

-   -   a first component, component A, which consists of one or more        compounds of the above-mentioned formula I, and    -   one or more further components selected from the group of        components B to E defined below,    -   a strongly dielectrically positive component, component B, which        has a dielectric anisotropy of 10.0 or more,    -   a strongly dielectrically negative component, component C, which        has a dielectric anisotropy of −5.0 or less,    -   a further component, component D, which has a dielectric        anisotropy in the range from more than −5.0 to less than 10.0        and consists of compounds having seven or more, preferably eight        or more, five- or six-membered rings, and    -   a further component, component E, which likewise has a        dielectric anisotropy in the range from more than −5.0 to less        than 10.0 and consists of compounds having up to six five- or        six-membered rings.

Typical examples of five-membered rings are

and others.

Typical examples of six-membered rings are

The five- and six-membered rings also include saturated and partiallysaturated rings, as well as heterocyclic rings.

For the purposes of the present application, condensed ring systemswhich consist of two of these rings, i.e. two five-membered rings, onefive-membered ring or two six-membered rings, such as, for example,

are counted as one of these five- or six-membered rings on assignment ofthe compounds to components A or D.

Correspondingly, condensed ring systems which consist of a combinationof three or more of these rings which are incorporated into the moleculein the longitudinal direction, such as, for example,

are counted as two of these five- or six-membered rings.

By contrast, condensed ring systems which are incorporated into themolecule in the transverse direction, such as, for example,

are counted as one of these five- or six-membered rings.

The present invention likewise relates to the directly precedingliquid-crystalline media and to those described below, and to the usethereof in electro-optical displays and in particular in components forhigh-frequency technology.

In a preferred embodiment of the present invention, the liquid-crystalmedium comprises one or more compounds of the formula I, preferablyselected from the group of the compounds of the formulae I-1 to I-4,preferably of the formulae I-1 and/or I-2 and/or I-3 and/or I-4,preferably of the formulae I-1 and I-2, these compounds more preferablypredominantly consist thereof, even more preferably essentially consistthereof and very particularly preferably completely consist thereof:

in which

-   L¹ denotes alkyl having 1 to 6 C atoms, alkenyl having 2 to 6 C    atoms, cycloalkyl having 3 to 6 C atoms or cycloalkenyl having 4 to    6 C atoms, preferably CH₃, C₂H₅, n-C₃H₇ (—(CH₂)₂CH₃), i-C₃H₇    (—CH(CH₃)₂), —CH═CH₂, cyclopropyl, cyclobutyl, cyclopentyl,    cyclohexyl, cyclopent-1-enyl or cyclohex-1-enyl, and particularly    preferably CH₃, C₂H₅, cyclopropyl or cyclobutyl,-   X¹ denotes H, alkyl having 1 to 3 C atoms or halogen, preferably H,    F or Cl, and particularly preferably H, F or CH₃, even more    preferably H or F and very particularly preferably F,    and the other parameters have the respective meanings indicated    above for formula I, and preferably-   R¹¹ denotes unfluorinated alkyl having 1 to 7 C atoms, and-   R¹² denotes unfluorinated alkyl having 1 to 7 C atoms or    unfluorinated alkoxy having 1 to 7 C atoms.

In a particularly preferred embodiment of the present invention, theliquid-crystal medium comprises one or more compounds of the formulaI-1, preferably selected from the group of the compounds of the formulaeI-1a-1 to I-1a-12 and I-1b-1 to I-1b-12

in which the parameters have the meanings as given above under formulaI-1, and preferably

R¹¹ and R¹², independently of one another, denote an alkyl radicalhaving 2 to 7 C atoms, for example a propyl or hexyl radical, or eachdenote a propyl, butyl, pentyl or hexyl radical.

In a very particularly preferred embodiment of the present invention,the liquid-crystal medium, or component A of the liquid-crystal medium,comprises one or more compounds of the formula I, preferably selectedfrom the group of the compounds of the formulae I-1a-2, I-1a-5, I-1a-7,I-1a-8, I-1a-9, I-1a-10, I-1b-5, I-1b-7, I-1b-8, I-1b-9, I-1b-10, wherethe parameters have the meaning given above, and particularly preferably

-   R¹¹ and R¹², independently of one another, denote unfluorinated    alkyl having 1 to 7 C atoms or unfluorinated alkoxy having 1 to 6 C    atoms,    particularly preferably one of-   R¹¹ and R¹² denotes alkyl and the other denotes alkyl or alkoxy,    and very particularly preferably R¹¹ and R¹² have different meanings    from one another.

In a preferred embodiment of the present invention, the liquid-crystalmedium, or component A of the liquid-crystal medium, comprises one ormore compounds of the formula I-2,

in which preferably

R¹¹ and R¹², independently of one another, denote an alkyl radicalhaving 2 to 7 C atoms, for example a propyl or hexyl radical, or eachdenote a propyl, butyl, pentyl or hexyl radical.

In a preferred embodiment of the present invention, the liquid-crystalmedium, or component A of the liquid-crystal medium, comprises one ormore compounds of the formula I-3, preferably selected from the group ofthe compounds of the formulae I-3a-1 to I-3a-3 and I-3b-1 to I-3b-3,preferably I-3a-2, I-3b-2,

in which the parameters have the meanings given above under formula I-3,and preferably

R¹¹ and R¹², independently of one another, denote an alkyl radicalhaving 2 to 7 C atoms, for example a propyl or hexyl radical, or eachdenote a propyl, butyl, pentyl or hexyl radical.

In a preferred embodiment of the present invention, the liquid-crystalmedium, or component A of the liquid-crystal medium, comprises one ormore compounds of the formula I-4, preferably selected from the group ofthe compounds of the formulae I-4a-1 to I-4a-3 and I-4b-1 to I-4b-3,preferably I-4b-2,

in which the parameters have the meanings given above under formula I-4,and preferably

R¹¹ and R¹², independently of one another, denote an alkyl radicalhaving 2 to 7 C atoms, for example a propyl or hexyl radical, or eachdenote a propyl, butyl, pentyl or hexyl radical.

The compounds of the formula I-1a can advantageously be prepared asevident from the following illustrative synthesis (Scheme 1-4):

The compounds of the formula I-1b can advantageously be obtained inaccordance with the following general reaction schemes (reaction schemes5 to 11). The parameters L¹, R¹¹, R¹² and X¹ therein are as definedabove and below. R has the meaning of R¹¹ or R¹².

Schemes 7 to 11 show the synthesis of variously substituted centralrings. The phenylalkynyl radicals here can be generalised to any desiredsubstituted phenylalkynyl radicals.

The compounds of the formula I-2 can advantageously be prepared asevident from the following illustrative synthesis (Scheme 12):

1,4-Dibromonaphthalene is subjected to a halogen-metal exchange reactionand converted into 1-iodo-4-bromonaphthalene. This is firstly convertedselectively into the monofunctionalised acetylene-bridged compound in aSonogashira coupling, followed by a second Sonogashira reaction, inwhich the target compounds of the formula I having two acetylene bridgesare obtained. If the two groups R are identical, coupling to twoequivalents of the acetylene compound can be carried out immediatelyinstead of the iodination.

The compounds of the formulae I-3 and I-4 can advantageously be obtainedin accordance with the following general reaction scheme (ReactionScheme 13).

Besides component A, these media according to the invention preferablycomprise a component selected from the two components B and C andoptionally additionally component D and/or component E.

These media according to the invention preferably comprise two, three orfour, particularly preferably two or three, components selected from thegroup of components A to E. These media preferably comprise

-   -   component A and component B, or    -   component A, component B and component D and/or E, or    -   component A and component C, or    -   component A, component B and component C, or    -   component A, component C and component D and/or E.

These media according to the invention preferably comprise a component Band no component C or vice versa.

The strongly dielectrically positive component, component B, preferablyhas a dielectric anisotropy of 20.0 or more, more preferably 25.0 ormore, particularly preferably 30.0 or more and very particularlypreferably 40.0 or more.

The strongly dielectrically negative component, component C, preferablyhas a dielectric anisotropy of −7.0 or less, more preferably −8.0 orless, particularly preferably −10.0 or less and very particularlypreferably −15.0 or less.

In a preferred embodiment of the present invention, component Bcomprises one or more compounds selected from the group of the compoundsof the formulae IIA and IIB:

-   R²¹ denotes unfluorinated alkyl or unfluorinated alkoxy, each having    1 to 15 C atoms, or unfluorinated alkenyl, unfluorinated alkenyloxy    or unfluorinated alkoxyalkyl, each having 2 to 15 C atoms,    preferably alkyl, particularly preferably n-alkyl,-   R²² denotes H, unfluorinated alkyl or unfluorinated alkoxy, each    having 1 to 5, preferably 1 to 3, particularly preferably 3, C    atoms,

-   -    to

-   -    independently of one another and, if they occur more than once,        these also in each case independently of one another, denote

preferably

-   n and m, independently of one another, denote 1 or 2, preferably-   (n+m) denotes 3 or 4, and particularly preferably-   n denotes 2,-   X² denotes F, Cl, —CF₃ or —OCF₃, preferably F or Cl, particularly    preferably F,-   Y² denotes F, Cl, —CF₃, —OCF₃ or CN, preferably CN, and-   Z² denotes H or F.

Preferred compounds of the formula IIA are the compounds of thecorresponding sub-formula IIA-1

in which R²¹ has the meaning given above.

Preferred compounds of the formula IIB are the compounds of thecorresponding sub-formulae IIB-1 and IIB-2:

in which R²¹, R²² and X² have the respective meanings given above.

In a preferred embodiment of the present invention, component Ccomprises one or more compounds selected from the group of the compoundsof the formulae IIIA and IIIB:

in which

-   R³¹ and R³², independently of one another, have the meanings    indicated above for R²¹ under formula IIA,    and preferably-   R³¹ denotes C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z) and-   R³² denotes C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂,    and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R³¹ and R³²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)).

Preferred compounds of the formula MB are the compounds of thesub-formulae IIIB-1 and IIIB-2:

in which

-   n and m each have the meanings given above for formula MB and    preferably, independently of one another, denote an integer in the    range from 1 to 7.

In a preferred embodiment of the present invention, component Dcomprises one or more compounds of the following formula IV:

in which

-   R⁴¹ and R⁴², independently of one another, have one of the meanings    indicated above for R¹¹ under formula I,-   L⁴¹ to L⁴⁴ on each appearance, in each case independently of one    another, denote H, alkyl having 1 to 5 C atoms, F or Cl, and-   P denotes an integer in the range from 7 to 14, preferably from 8 to    12 and particularly preferably from 9 to 10,    and preferably    at least two of the substituents-   L⁴¹ to L⁴⁴ present have a meaning other than H, and-   R⁴¹ denotes C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁴² denotes C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂,    and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

In a preferred embodiment of the present application, the liquid-crystalmedium additionally comprises a further component, component E, whichpreferably consists of one or more compounds selected from the group ofthe compounds of the formulae V to IX:

in which

-   L⁵¹ denotes R⁵¹ or X⁵¹,-   L⁵² denotes R⁵² or X⁵²,-   R⁵¹ and R⁵², independently of one another, denote H, unfluorinated    alkyl or unfluorinated alkoxy having 1 to 17, preferably 3 to 10, C    atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or    unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C    atoms, preferably alkyl or unfluorinated alkenyl,-   X⁵¹ and X⁵², independently of one another, denote H, F, Cl, —CN,    —NCS, —SF₅, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C    atoms or fluorinated alkenyl, unfluorinated or fluorinated    alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7    C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or    Cl, and

-   -    to

-   -    independently of one another, denote

preferably

-   L⁶¹ denotes R⁶¹ and, in the case where Z⁶¹ and/or Z⁶² denote    trans-CH═CH— or trans-CF═CF—, alternatively also denotes X⁶¹,-   L⁶² denotes R⁶² and, in the case where Z⁶¹ and/or Z⁶² denote    trans-CH═CH— or trans-CF═CF—, alternatively also denotes X⁶²,-   R⁶¹ and R⁶², independently of one another, denote H, unfluorinated    alkyl or unfluorinated alkoxy having 1 to 17, preferably 3 to 10, C    atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or    unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C    atoms, preferably alkyl or unfluorinated alkenyl,-   X⁶¹ and X⁶², independently of one another, denote F or Cl, —CN,    —NCS, —SF₅, fluorinated alkyl or alkoxy having 1 to 7 C atoms or    fluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C    atoms, preferably —NCS,    one of-   Z⁶¹ and Z⁶² denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and the    other, independently thereof, denotes trans-CH═CH—, trans-CF═CF— or    a single bond, preferably one of them denotes —C═C— or trans-CH═CH—    and the other denotes a single bond, and

-   -    to

-   -    independently of one another, denote

preferably

-   L⁷¹ denotes R⁷¹ or X⁷¹,-   L⁷² denotes R⁷² or X⁷²,-   R⁷¹ and R⁷², independently of one another, denote H, unfluorinated    alkyl or unfluorinated alkoxy having 1 to 17, preferably 3 to 10, C    atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or    unfluorinated alkoxyalkyl having 2 to 15, preferably 3 to 10, C    atoms, preferably alkyl or unfluorinated alkenyl,-   X⁷¹ and X⁷², independently of one another, denote H, F, Cl, —CN,    —NCS, —SF₅, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C    atoms or fluorinated alkenyl, unfluorinated or fluorinated    alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7    C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or    Cl, and-   Z⁷¹ to Z⁷³, independently of one another, denote trans-CH═CH—,    trans-CF═CF—, —C≡C— or a single bond, preferably one or more of them    denote a single bond, particularly preferably all denote a single    bond and

-   -    to

-   -    independently of one another, denote

preferably

-   R⁸¹ and R⁸², independently of one another, denote H, unfluorinated    alkyl or alkoxy having 1 to 15, preferably 3 to 10, C atoms or    unfluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15,    preferably 3 to 10, C atoms, preferably unfluorinated alkyl or    alkenyl,    one of-   Z⁸¹ and Z⁸² denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and the    other, independently thereof, denotes trans-CH═CH—, trans-CF═CF— or    a single bond, preferably one of them denotes —C═C— or trans-CH═CH—    and the other denotes a single bond, and

denotes

and

-   -   independently of one another, denote

-   L⁹¹ denotes R⁹¹ or X⁹¹,-   L⁹² denotes R⁹² or X⁹²,-   R⁹¹ and R⁹², independently of one another, denote H, unfluorinated    alkyl or alkoxy having 1 to 15, preferably 3 to 10, C atoms or    unfluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15,    preferably 3 to 10, C atoms, preferably unfluorinated alkyl or    alkenyl,-   X⁹¹ and X⁹², independently of one another, denote H, F, Cl, —CN,    —NCS, —SF₅, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C    atoms or fluorinated alkenyl, unfluorinated or fluorinated    alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7    C atoms, preferably fluorinated alkoxy, fluorinated alkenyloxy, F or    Cl, and-   Z⁹¹ to Z⁹³, independently of one another, denote trans-CH═CH—,    trans-CF═CF—, —C≡C— or a single bond, preferably one or more of them    denotes a single bond, and particularly preferably all denote a    single bond,

denotes

to

-   -   independently of one another, denote

and where compounds of the formula MA are excluded from the compounds ofthe formula VI.

In a preferred embodiment of the present invention, the liquid-crystalmedium comprises, more preferably predominantly consists of, even morepreferably essentially consists of and very particularly preferablycompletely consists of one or more compounds of the formula V,preferably selected from the group of the compounds of the formulae V-1to V-3, preferably of the formulae V-1 and/or V-2 and/or V-3, preferablyof the formulae V-1 and V-2:

in which the parameters have the respective meanings indicated above forformula V and preferably

-   R⁵¹ denotes unfluorinated alkyl having 1 to 7 C atoms or    unfluorinated alkenyl having 2 to 7 C atoms,-   R⁵² denotes unfluorinated alkyl having 1 to 7 C atoms or    unfluorinated alkenyl having 2 to 7 C atoms or unfluorinated alkoxy    having 1 to 7 C atoms,-   X⁵¹ and X⁵², independently of one another, denote F, Cl, —OCF₃,    —CF₃, —CN, —NCS or —SF₅, preferably F, Cl, —OCF₃ or —CN.

The compounds of the formula V-1 are preferably selected from the groupof the compounds of the formulae V-1a to V-1d, more preferably thesecompounds of the formula V predominantly consist, even more preferablyessentially consist and very particularly preferably completely consistthereof:

in which the parameters have the respective meanings indicated above forformula V-1 and in which

-   Y⁵¹ and Y⁵², in each case independently of one another, denote H or    F, and preferably-   R⁵¹ denotes alkyl or alkenyl, and-   X⁵¹ denotes F, Cl or —OCF₃.

The compounds of the formula V-2 are preferably selected from the groupof the compounds of the formulae V-2a to V-2e and/or from the group ofthe compounds of the formulae V-2f and V-2g, more preferably thesecompounds of the formula V predominantly consist, even more preferablyessentially consist and very particularly preferably completely consistthereof:

where in each case the compounds of the formula V-2a are excluded fromthe compounds of the formulae V-2b and V-2c, the compounds of theformula V-2b are excluded from the compounds of the formula V-2c and thecompounds of the formula V-2e are excluded from the compounds of theformula V-2f, and in which the parameters have the respective meaningsindicated above for formula V-1 and in which

-   Y⁵¹ and Y⁵², in each case independently of one another, denote H or    F, and preferably-   R⁵¹ denotes alkyl or alkenyl,-   X⁵¹ denotes F, Cl or —OCF₃, and preferably one of-   Y⁵¹ and Y⁵² denotes H and the other denotes H or F, preferably    likewise denotes H.

The compounds of the formula V-3 are preferably compounds of the formulaV-3a:

in which the parameters have the respective meanings indicated above forformula V-1 and in which preferably

-   X⁵¹ denotes F, Cl, preferably F,-   X⁵² denotes F, Cl or —OCF₃, preferably —OCF₃.

In an even more preferred embodiment of the present invention, thecompounds of the formula V are selected from the group of the compoundsV-1a to V-1d, preferably selected from the group of the compounds V-1cand V-1d, more preferably these compounds of the formula V predominantlyconsist, even more preferably essentially consist and very particularlypreferably completely consist thereof:

The compounds of the formula V-1a are preferably selected from the groupof the compounds of the formulae V-1a-1 and V-1a-2, more preferablythese compounds of the formula V predominantly consist, even morepreferably essentially consist and very particularly preferablycompletely consist thereof:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 0 to 7, preferably in the    range from 1 to 5 and particularly preferably 3 or 7.

The compounds of the formula V-1b are preferably compounds of theformula V-1b-1:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 0 to 15, preferably in the    range from 1 to 7 and particularly preferably 1 to 5.

The compounds of the formula V-1c are preferably selected from the groupof the compounds of the formulae V-1c-1 to V-1c-4, preferably selectedfrom the group of the compounds of the formulae V-1c-1 and V-1c-2, morepreferably these compounds of the formula V predominantly consist, evenmore preferably essentially consist and very particularly preferablycompletely consist thereof:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 0 to 15, preferably in the    range from 1 to 7 and particularly preferably 1 to 5.

The compounds of the formula V-1d are preferably selected from the groupof the compounds of the formulae V-1d-1 and V-1d-2, preferably thecompound of the formula V-1d-2, more preferably these compounds of theformula V predominantly consist, even more preferably essentiallyconsist and very particularly preferably completely consist thereof:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 0 to 15, preferably in the    range from 1 to 7 and particularly preferably 1 to 5.

The compounds of the formula V-2a are preferably selected from the groupof the compounds of the formulae V-2a-1 and V-2a-2, preferably thecompounds of the formula V-2a-1, more preferably these compounds of theformula V predominantly consist, even more preferably essentiallyconsist and very particularly preferably completely consist thereof:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

Preferred combinations of (R⁵¹ and R⁵²), in particular in the case offormula V-2a-1, are (C_(n)H_(2n+1) and C_(m)H_(2m+1)), (C_(n)H_(2n+1)and O—C_(m)H_(2m+1)), (CH₂═CH—(CH₂)_(z) and C_(m)H_(2m+1)),(CH₂═CH—(CH₂)_(z) and O—C_(m)H_(2m+1)) and (C_(n)H_(2n+1) and(CH₂)_(z)—CH═CH₂).

Preferred compounds of the formula V-2b are the compounds of the formulaV-2b-1:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁵¹ and R⁵²) here is, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

Preferred compounds of the formula V-2c are the compounds of the formulaV-2c-1:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁵¹ and R⁵²) here is, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

Preferred compounds of the formula V-2d are the compounds of the formulaV-2d-1:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C₁H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁵¹ and R⁵²) here is, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

Preferred compounds of the formula V-2e are the compounds of the formulaV-2e-1:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C₁H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁵¹ and R⁵²) here is, in particular,(C_(n)H_(2n+1) and O—C_(m)H_(2m+1)).

Preferred compounds of the formula V-2f are the compounds of the formulaV-2f-1:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁵¹ and R⁵²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

Preferred compounds of the formula V-2g are the compounds of the formulaV-2g-1:

in which

-   R⁵¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁵² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁵¹ and R⁵²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)).

The compounds of the formula VI are preferably selected from the groupof the compounds of the formulae VI-1 to VI-4, more preferably thesecompounds of the formula VI predominantly consist, even more preferablyessentially consist and very particularly preferably completely consistthereof:

in which

-   Z⁶¹ and Z⁶² denote trans-CH═CH— or trans-CF═CF—, preferably    trans-CH═CH—, and the other parameters have the meaning given above    under formula VI and preferably-   R⁶¹ and R⁶², independently of one another, denote H, unfluorinated    alkyl or alkoxy having 1 to 7 C atoms or unfluorinated alkenyl    having 2 to 7 C atoms,-   X⁶² denotes F, Cl, —CN or —NCS, preferably —NCS,    and one of

to

denotes

-   -   and the others, independently of one another, denote

preferably

and preferably

-   R⁶¹ denotes C₁H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁶² denotes C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂,    and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of the formula VI-1 are preferably selected from the groupof the compounds of the formulae VI-1a and VI-1b, preferably selectedfrom compounds of the formula VI-1a, more preferably these compounds ofthe formula VI predominantly consist, even more preferably essentiallyconsist and very particularly preferably completely consist thereof:

in which

-   R⁶¹-   has the meaning indicated above and preferably denotes C_(n)H_(2n+1)    or CH₂═CH—(CH₂)_(z), and-   R⁶² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁶¹ and R⁶²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), in the case of formula VI-1a particularly preferably(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and in the case of formula VI-1bparticularly preferably (C_(n)H_(2n+1) and O—C_(m)H_(2m+1)).

The compounds of the formula VI-3 are preferably compounds of theformula VI-3a:

in which the parameters have the meaning given above under formula VI-3and preferably

-   R⁶¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes an integer in the range from 0 to 7, preferably in the    range from 1 to 5, and-   X⁶² denotes —F, —Cl, —OCF₃, —CN or —NCS, particularly preferably    —NCS.

The compounds of the formula VI-4 are preferably compounds of theformula VI-4a:

in which the parameters have the meaning given above under formula VI-4and preferably

R⁶¹ has the meaning indicated above and preferably denotesC_(n)H_(2n+1), in which

-   n denotes an integer in the range from 0 to 7, preferably in the    range from 1 to 5, and-   X⁶² denotes F, Cl, OCF₃, —CN or —NCS, particularly preferably —NCS.

Further preferred compounds of the formula VI are the compounds of thefollowing formulae:

in which

-   n denotes an integer in the range from 0 to 7, preferably in the    range from 1 to 5.

The compounds of the formula VII are preferably selected from the groupof the compounds of the formulae VII-1 to VII-6, more preferably thesecompounds of the formula VII predominantly consist, even more preferablyessentially consist and very particularly preferably completely consistthereof:

where the compounds of the formula VII-5 are excluded from the compoundsof the formula VII-6, and

in which the parameters have the respective meanings indicated above forformula VII, and preferably

-   R⁷¹ denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C    atoms, or unfluorinated alkenyl having 2 to 7 C atoms,-   R⁷² denotes unfluorinated alkyl or alkoxy, each having 1 to 7 C    atoms, or unfluorinated alkenyl having 2 to 7 C atoms, and-   X⁷² denotes F, Cl or —OCF₃, preferably F, and    particularly preferably-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m±i) or O—C_(m)H_(2m±i) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The compounds of the formula VII-1 are preferably selected from thegroup of the compounds of the formulae VII-1a to VII-1d, more preferablythese compounds of the formula VII-1 predominantly consist, even morepreferably essentially consist and very particularly preferablycompletely consist thereof:

in which X⁷² has the meaning given above for formula VII-2 and

-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), in which-   n denotes 1 to 7, preferably 2 to 6, particularly preferably 2, 3 or    5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2, and-   X⁷² preferably denotes F.

The compounds of the formula VII-2 are preferably selected from thegroup of the compounds of the formulae VII-2a and VII-2b, preferably ofthe formula VII-2a, more preferably these compounds of the formula VII-2predominantly consist, even more preferably essentially consist and veryparticularly preferably completely consist thereof:

in which

-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VII-3 are preferably compounds of theformula VII-3a:

in which

-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VII-4 are preferably compounds of theformula VII-4-a:

in which

-   R⁷¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VII-5 are preferably selected from thegroup of the compounds of the formulae VII-5a and VII-5b, preferably ofthe formula VII-5a, more preferably these compounds of the formula VII-5predominantly consist, even more preferably essentially consist and veryparticularly preferably completely consist thereof:

in which

-   R⁷¹ has the meaning indicated above and preferably denotes    C₁H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VII-6 are preferably selected from thegroup of the compounds of the formulae VII-6a and VII-6b, morepreferably these compounds of the formula VII-6 predominantly consist,even more preferably essentially consist and very particularlypreferably completely consist thereof:

in which

-   R⁷¹ has the meaning indicated above and preferably denotes    C₁H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁷² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁷¹ and R⁷²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The liquid-crystalline media in accordance with the present applicationpreferably comprise in total 0 to 40%, preferably 0 to 30% andparticularly preferably 5 to 25%, of compounds of the formula VIII.

The compounds of the formula VIII are preferably selected from the groupof the compounds of the formulae VIII-1 to VIII-3, more preferably thesecompounds of the formula VIII predominantly consist, even morepreferably essentially consist and very particularly preferablycompletely consist thereof:

in whichone of

-   Y⁸¹ and Y⁸² denotes H and the other denotes H or F, and-   R⁸¹ has the meaning indicated above and preferably denotes    C₁H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁸² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁸¹ and R⁸²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VIII-1 are preferably selected from thegroup of the compounds of the formulae VIII-1a to VIII-1c, morepreferably these compounds of the formula VIII-1 predominantly consist,even more preferably essentially consist and very particularlypreferably completely consist thereof:

in which

-   R⁸¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁸² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁸¹ and R⁸²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andC_(m)H_(2m+1)).

The compounds of the formula VIII-2 are preferably compounds of theformula VIII-2a:

in which

-   R⁸¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁸² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁸¹ and R⁸²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)), (C₁H_(2n+1) and O—C_(m)H_(2m+1)) and(CH₂═CH—(CH₂)_(z) and C_(m)H_(2m+1)), particularly preferably(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

The compounds of the formula VIII-3 are preferably compounds of theformula VIII-3a:

in which

-   R⁸¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁸² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁸¹ and R⁸²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)).

The compounds of the formula IX are preferably selected from the groupof the compounds of the formulae IX-1 to IX-3, more preferably thesecompounds of the formula IX predominantly consist, even more preferablyessentially consist and very particularly preferably completely consistthereof:

in which the parameters have the respective meaning indicated aboveunder formula IX and preferablyone of

to

denotes

andin which

-   R⁹¹ has the meaning indicated above and preferably denotes    C₁H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁹² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁹¹ and R⁹²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)).

The liquid-crystalline media in accordance with the present applicationpreferably comprise in total 5 to 30%, preferably 10 to 25% andparticularly preferably 15 to 20%, of compounds of the formula IX.

The compounds of the formula IX-1 are preferably selected from the groupof the compounds of the formulae IX-1a to IX-1e, more preferably thesecompounds of the formula IX-1 predominantly consist, even morepreferably essentially consist and very particularly preferablycompletely consist thereof:

in which the parameters have the meaning given above and preferably

-   R⁹¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1), and-   n denotes an integer in the range from 0 to 15, preferably in the    range from 1 to 7 and particularly preferably 1 to 5, and-   X⁹² preferably denotes F or Cl.

The compounds of the formula IX-2 are preferably selected from the groupof the compounds of the formulae IX-2a and IX-2b, more preferably thesecompounds of the formula IX-2 predominantly consist, even morepreferably essentially consist and very particularly preferablycompletely consist thereof:

in which

-   R⁹¹ has the meaning indicated above and preferably denotes    C_(n)H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁹² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combination of (R⁹¹ and R⁹²) here is, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)).

The compounds of the formula IX-3 are preferably compounds of theformulae IX-3a and IX-3b:

in which

-   R⁹¹ has the meaning indicated above and preferably denotes    C₁H_(2n+1) or CH₂═CH—(CH₂)_(z), and-   R⁹² has the meaning indicated above and preferably denotes    C_(m)H_(2m+1) or O—C_(m)H_(2m+1) or (CH₂)_(z)—CH═CH₂, and in which-   n and m, independently of one another, denote an integer in the    range from 0 to 15, preferably in the range from 1 to 7 and    particularly preferably 1 to 5, and-   z denotes 0, 1, 2, 3 or 4, preferably 0 or 2.

The preferred combinations of (R⁹¹ and R⁹²) here are, in particular,(C_(n)H_(2n+1) and C_(m)H_(2m+1)) and (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)), particularly preferably (C_(n)H_(2n+1) andO—C_(m)H_(2m+1)).

In a preferred embodiment of the present invention, the medium comprisesone or more dielectrically positive compounds of the formula V-1 havinga dielectric anisotropy of greater than 3.

The liquid-crystalline media in accordance with the present inventionpreferably comprise 10% or less, preferably 5% or less, particularlypreferably 2% or less, very particularly preferably 1% or less, and inparticular absolutely no compound having only two or fewer five- and/orsix-membered rings.

In a preferred embodiment of the present invention, the medium comprisesone or more compounds of the formula VI.

In a further preferred embodiment of the present invention, the mediumcomprises one or more compounds of the formula VII.

The definitions of the abbreviations (acronyms) used for the compoundsin the present application are indicated below in Table D or are evidentfrom Tables A to C.

In a preferred embodiment of the present invention, the liquid-crystalmedium, or component A of the liquid-crystal medium, comprises one ormore compounds of the formulae I-1 and/or I-2 and/or I-3 and/or I-4.

The liquid-crystal medium, or component A of the liquid-crystal medium,preferably comprises one or more compounds selected from the compoundsof the formulae I-1a-1 to I-1a-12, particularly preferably of theformula I-1a-2, very particularly preferably one or more compounds ofthe formula I-1a-2 and one or more compounds selected from the group ofthe compounds of the formula I-1a-1 and formulae I-1a-3 to I-1a-12, andone or more compounds of the formulae I-1b-1 to I-1b-12 and/or I-2and/or I-3 and/or I-4.

In a further preferred embodiment of the present invention, theliquid-crystal medium, or component A of the liquid-crystal medium,comprises one or more compounds selected from the group of the compoundsof the formulae I-1b-1 to I-1b-12, particularly preferably selected fromthe group of the compounds of the formulae I-1b-5 and/or I-1b-7 and/orI-1b-8 and/or I-1b-9 and/or I-1b-10, and one or more compounds selectedfrom the group of the compounds of the formulae I-1a-1 to I-1a-12,preferably of the formula I-1a-2, and/or one or more compounds of theformulae I-2 and/or I-3 and/or I-4.

In a further preferred embodiment of the present invention, theliquid-crystal medium, or component A of the liquid-crystal medium,comprises one or more compounds of the formula I-2 and one or morecompounds of the formula I-1, preferably of the formula I-1a, preferablyof the formulae I-1a-2, and/or I-1b, and/or one or more compounds of theformulae I-3 and/or I-4.

In a further preferred embodiment of the present invention, theliquid-crystal medium, or component A of the liquid-crystal medium,comprises one or more compounds of the formula I-3 and one or morecompounds of the formula I-1, preferably of the formula I-1a, preferablyof the formula I-1a-2, and/or I-1b, and/or one or more compounds of theformulae I-2 and/or I-4.

In a further preferred embodiment of the present invention, theliquid-crystal medium, or component A of the liquid-crystal medium,comprises one or more compounds of the formula I-4 and one or morecompounds of the formula I-1, preferably of the formula I-1a, preferablyof the formula I-1a-2, and/or I-1b, and/or one or more compounds of theformulae I-2 and/or I-3.

The liquid-crystalline media in accordance with the present inventionpreferably comprise, more preferably predominantly consist of, even morepreferably essentially consist of and very particularly preferablycompletely consist of compounds selected from the group of the compoundsof the formulae I, II, IV and V, preferably I, II and IV, or selectedfrom the group of the compounds of the formulae I, III, IV and V,preferably I, III and IV.

In this application, comprise in connection with compositions means thatthe entity in question, i.e. the medium or the component, comprises thecomponent or components or compound or compounds indicated, preferablyin a total concentration of 10% or more and very preferably 20% or more.

In this connection, predominantly consist of means that the entity inquestion comprises 55% or more, preferably 60% or more and verypreferably 70% or more, of the component or components or compound orcompounds indicated.

In this connection, essentially consist of means that the entity inquestion comprises 80% or more, preferably 90% or more and verypreferably 95% or more, of the component or components or compound orcompounds indicated.

In this connection, completely consist of means that the entity inquestion comprises 98% or more, preferably 99% or more and verypreferably 100.0% of the component or components or compound orcompounds indicated.

Other mesogenic compounds which are not explicitly mentioned above canoptionally and advantageously also be used in the media in accordancewith the present invention. Such compounds are known to the personskilled in the art.

The liquid-crystal media in accordance with the present inventionpreferably have a clearing point of 90° C. or more, more preferably 100°C. or more, even more preferably 120° C. or more, particularlypreferably 150° C. or more and very particularly preferably 170° C. ormore.

The nematic phase of the media according to the invention preferablyextends at least from 20° C. or less to 90° C. or more, preferably up to100° C. or more, more preferably at least from 0° C. or less to 120° C.or more, very preferably at least from −10° C. or less to 140° C. ormore and in particular at least from −20° C. or less to 150° C. or more.

The Δ∈ of the liquid-crystal medium in accordance with the invention, at1 kHz and 20° C., is preferably 1 or more, more preferably 2 or more andvery preferably 3 or more.

The Δn of the liquid-crystal media in accordance with the presentinvention, at 589 nm (Na^(D)) and 20° C., is preferably in the rangefrom 0.200 or more to 0.90 or less, more preferably in the range from0.250 or more to 0.90 or less, even more preferably in the range from0.300 or more to 0.85 or less and very particularly preferably in therange from 0.350 or more to 0.800 or less.

In a preferred embodiment of the present application, the Δn of theliquid-crystal media in accordance with the present invention ispreferably 0.40 or more, more preferably 0.45 or more.

In accordance with the present invention, the individual compounds ofthe formula I in the liquid-crystal media are preferably used in a totalconcentration of 10% to 100%, more preferably 30% to 95%, even morepreferably 40% to 90% and very preferably 50% to 90%, of the mixture asa whole.

In the embodiment of the present invention in which the liquid-crystalmedia comprise one or more compounds selected from the group of thecompounds of the formulae IIA and IIB, the further compounds arepreferably employed as follows.

The compounds selected from the group of the compounds of the formulaeIIA and IIB are preferably used in a total concentration of 1% to 30%,more preferably 2% to 20%, even more preferably 3% to 18% and verypreferably 4% to 16%, of the mixture as a whole.

The compounds of the formula IV are preferably used in a totalconcentration of 1% to 20%, more preferably 2% to 15%, even morepreferably 3% to 12% and very preferably 5% to 10%, of the mixture as awhole.

The liquid-crystal media preferably comprise, more preferablypredominantly consist of and very preferably completely consist of intotal 70% to 100%, more preferably 80% to 100% and very preferably 90%to 100% and in particular 95% to 100%, of the compounds of the formulaeI, IIA, IIB and IV to IX, preferably of the formulae I, IIA, IIB and IV.

In the embodiment of the present invention in which the liquid-crystalmedia comprise one or more compounds selected from the group of thecompounds of the formulae IIIA and IIIB, the further compounds arepreferably employed as follows.

The compounds selected from the group of the compounds of the formulaeIIIA and IIIB are preferably used in a total concentration of 1% to 60%,more preferably 5% to 55%, even more preferably 7% to 50% and verypreferably 10% to 45%, of the mixture as a whole.

If the liquid-crystal media comprise only one or more compounds of theformula IIIA, but no compounds of the formula IIIB, the compounds of theformula IIIA are preferably used in a total concentration of 10% to 60%,more preferably 20% to 55%, even more preferably 30% to 50% and verypreferably 35% to 45%, of the mixture as a whole.

If the liquid-crystal media comprise only one or more compounds of theformula IIIB, but no compounds of the formula IIIA, the compounds of theformula IIIB are preferably used in a total concentration of 5% to 45%,more preferably 10% to 40%, even more preferably 15% to 35% and verypreferably 20% to 30%, of the mixture as a whole.

If the liquid-crystal media comprise both one or more compounds of theformula IIIA and one or more compounds of the formula IIIB, thecompounds of the formula IIIA are preferably used in a totalconcentration of 5% to 50%, more preferably 10% to 45%, even morepreferably 15% to 30% and very preferably 20% to 25%, of the mixture asa whole and the compounds of the formula IIIB are preferably used in atotal concentration of 1% to 35%, more preferably 5% to 30%, even morepreferably 7% to 25% and very preferably 10% to 20%, of the mixture as awhole.

The compounds of the formula IV are preferably used in a totalconcentration of 1% to 20%, more preferably 2% to 15%, even morepreferably 3% to 12% and very preferably 5% to 10%, of the mixture as awhole.

The liquid-crystal media preferably comprise, more preferablypredominantly consist of and very preferably completely consist of intotal 70% to 100%, more preferably 80% to 100% and very preferably 90%to 100% and in particular 95% to 100%, of the compounds of the formulaeI, IIIA, MB and IV to IX, preferably of the formulae I, IIIA and/or MBand/or [lacuna].

In a particularly preferred embodiment of the present invention, theliquid-crystalline media comprise one or more compounds of the formula Vand one or more compounds of the formula VI.

In a further particularly preferred embodiment of the present invention,the liquid-crystalline media comprise one or more compounds of theformula V and one or more compounds of the formula VII.

The liquid-crystalline media in accordance with the present inventionlikewise preferably comprise one or more compounds of the formula V, oneor more compounds of the formula VI and one or more compounds of theformula VIII.

If the liquid-crystalline media in accordance with the presentapplication comprise one or more compounds of the formula V, theconcentration of these compounds is preferably in total 10 to 30%,preferably 15 to 25% and particularly preferably 18 to 22%.

If the liquid-crystalline media in accordance with the presentapplication comprise one or more compounds of the formula VI, theconcentration of these compounds is preferably in total 15 to 35%,preferably 18 to 30% and particularly preferably 22 to 26%.

If the liquid-crystalline media in accordance with the presentapplication comprise one or more compounds of the formula VII, theconcentration of these compounds is preferably in total 4 to 25%,preferably 8 to 20% and particularly preferably 10 to 14%.

If the liquid-crystalline media in accordance with the presentapplication comprise one or more compounds of the formula VIII, theconcentration of these compounds is preferably in total 15 to 35%,preferably 18 to 30% and particularly preferably 22 to 26%.

If the liquid-crystalline media in accordance with the presentapplication comprise one or more compounds of the formula IX, theconcentration of these compounds is preferably in total 5 to 25%,preferably 10 to 20% and particularly preferably 13 to 17%.

In the present application, the expression dielectrically positivedescribes compounds or components where Δ∈>3.0, dielectrically neutraldescribes those where −1.5≦Δ∈≦3.0 and dielectrically negative describesthose where Δ∈<−1.5. Δ∈ is determined at a frequency of 1 kHz and at 20°C. The dielectric anisotropy of the respective compound is determinedfrom the results of a solution of 10% of the respective individualcompound in a nematic host mixture. If the solubility of the respectivecompound in the host mixture is less than 10%, the concentration isreduced to 5%. The capacitances of the test mixtures are determined bothin a cell having homeotropic alignment and in a cell having homogeneousalignment. The cell thickness of both types of cells is approximately 20μm. The voltage applied is a rectangular wave having a frequency of 1kHz and an effective value of typically 0.5 V to 1.0 V, but it is alwaysselected to be below the capacitive threshold of the respective testmixture.

The following definitions apply here.

Δ∈≡(∈_(∥)−∈_(⊥)) and

∈_(average)=(∈_(∥)+2∈_(⊥))/3.

The host mixture used for dielectrically positive compounds is mixtureZLI-4792 and that used for dielectrically neutral and dielectricallynegative compounds is mixture ZLI-3086, both from Merck KGaA, Germany.The absolute values of the dielectric constants of the compounds aredetermined from the change in the respective values of the host mixtureon addition of the compounds of interest. The values are extrapolated toa concentration of the compounds of interest of 100%.

Components having a nematic phase at the measurement temperature of 20°C. are measured as such, all others are treated like compounds.

The expression threshold voltage in the present application refers tothe optical threshold and is quoted for 10% relative contrast (V₁₀), andthe expression saturation voltage refers to the optical saturation andis quoted for 90% relative contrast (V₉₀), in both cases unlessexpressly stated otherwise. The capacitive threshold voltage (V₀), alsocalled the Freedericks threshold (V_(F),), is only used if expresslymentioned.

The parameter ranges indicated in this application all include the limitvalues, unless expressly stated otherwise.

The different upper and lower limit values indicated for various rangesof properties in combination with one another give rise to additionalpreferred ranges.

Throughout this application, the following conditions and definitionsapply, unless expressly stated otherwise. All concentrations are quotedin percent by weight and relate to the respective mixture as a whole,all temperatures are quoted in degrees Celsius and all temperaturedifferences are quoted in differential degrees. All physical propertiesare determined in accordance with “Merck Liquid Crystals, PhysicalProperties of Liquid Crystals”, Status November 1997, Merck KGaA,Germany, and are quoted for a temperature of 20° C., unless expresslystated otherwise. The optical anisotropy (Δn) is determined at awavelength of 589.3 nm. The dielectric anisotropy (Δ∈) is determined ata frequency of 1 kHz. The threshold voltages, as well as all otherelectro-optical properties, are determined using test cells produced atMerck KGaA, Germany. The test cells for the determination of Δ∈ have acell thickness of approximately 20 μm. The electrode is a circular ITOelectrode having an area of 1.13 cm² and a guard ring. The orientationlayers are SE-1211 from Nissan Chemicals, Japan, for homeotropicorientation (∈_(∥)) and polyimide AL-1054 from Japan Synthetic Rubber,Japan, for homogeneous orientation (∈_(⊥)). The capacitances aredetermined using a Solatron 1260 frequency response analyser using asine wave with a voltage of 0.3 V.

The light used in the electro-optical measurements is white light. Aset-up using a commercially available DMS instrument fromAutronic-Melchers, Germany, is used here. The characteristic voltageshave been determined under perpendicular observation. The threshold(V₁₀), mid-grey (V₅₀) and saturation (V₉₀) voltages have been determinedfor 10%, 50% and 90% relative contrast, respectively.

The liquid-crystalline media are investigated with respect to theirproperties in the microwave frequency region as described in A.Penirschke et al., “Cavity Perturbation Method for Characterisation ofLiquid Crystals up to 35 GHz”, 34^(th) European MicrowaveConference—Amsterdam, pp. 545-548. Compare in this respect also A.Gaebler et al., “Direct Simulation of Material Permittivites . . . ”,12MTC 2009—International Instrumentation and Measurement TechnologyConference, Singapore, 2009 (IEEE), pp. 463-467, and DE 10 2004 029 429A, in which a measurement method is likewise described in detail.

The liquid crystal is introduced into a cylindricalpolytetrafluoroethylene (PTFE) or quartz capillary. The capillary has aninternal radius of 180 μm and an external radius of 350 μm. Theeffective length is 2.0 cm. The filled capillary is introduced into thecentre of the cylindrical cavity with a resonance frequency of 19 GHz.This cavity has a length of 11.5 mm and a radius of 6 mm. The inputsignal (source) is then applied, and the result of the output signal isrecorded using a commercial vector network analyser. For otherfrequencies, the dimensions of the cavity are adapted correspondingly.

The change in the resonance frequency and the Q factor between themeasurement with the capillary filled with the liquid crystal and themeasurement without the capillary filled with the liquid crystal is usedto determine the dielectric constant and the loss angle at thecorresponding target frequency by means of equations 10 and 11 of theabove-mentioned publication A. Penirschke et al., “Cavity PerturbationMethod for Characterisation of Liquid Crystals up to 35 GHz”, 34^(th)European Microwave Conference—Amsterdam, pp. 545-548, as describedtherein.

The values for the components of the properties perpendicular andparallel to the director of the liquid crystal are obtained by alignmentof the liquid crystal in a magnetic field. To this end, the magneticfield of a permanent magnet is used. The strength of the magnetic fieldis 0.35 tesla. The alignment of the magnet is set correspondingly andthen rotated correspondingly through 90°.

Preferred components are phase shifters, varactors, wireless and radiowave antenna arrays, matching circuit adaptive filters and others.

In the present application, the term compounds is taken to mean both onecompound and a plurality of compounds, unless expressly statedotherwise.

The liquid-crystal media according to the invention preferably havenematic phases of in each case at least from −20° C. to 80° C.,preferably from −30° C. to 85° C. and very particularly preferably from−40° C. to 100° C. The phase particularly preferably extends to 120° C.or more, preferably to 140° C. or more and very particularly preferablyto 160° C. or more. The expression have a nematic phase here means onthe one hand that no smectic phase and no crystallisation are observedat low temperatures at the corresponding temperature and on the otherhand that no clearing occurs on heating from the nematic phase. Theinvestigation at low temperatures is carried out in a flow viscometer atthe corresponding temperature and checked by storage in test cellshaving a layer thickness of 5 μm for at least 100 hours. At hightemperatures, the clearing point is measured in capillaries byconventional methods.

Furthermore, the liquid-crystal media according to the invention arecharacterised by high optical anisotropies in the visible region. Thebirefringence at 589 nm is preferably 0.20 or more, particularlypreferably 0.25 or more, particularly preferably 0.30 or more,particularly preferably 0.40 or more and very particularly preferably0.45 or more. In addition, the birefringence is preferably 0.80 or less.

In a preferred embodiment of the present invention, the liquid-crystalmedia employed have positive dielectric anisotropy ( ). This ispreferably 1.8 or more and 15.0 or less, more preferably between 2.0 ormore and 10.0 or less, particularly preferably between 3.0 or more and8.0 or less and very particularly preferably between 3.5 or more and 6.0or less.

If the liquid-crystal media employed have negative dielectric anisotropy( ), this is preferably less than or equal to −2.5, particularlypreferably less than or equal to −4.0 and very particularly preferablyless than or equal to −5.0.

In this preferred embodiment of the present invention, in which theliquid-crystal media employed have negative dielectric anisotropy ( ),the value thereof is preferably between 1.5 or more and 15.0 or less,particularly preferably between 1.8 or more and 12.0 or less and veryparticularly preferably between 2.0 or more and 10.0 or less.

Furthermore, the liquid-crystal media according to the invention arecharacterised by high anisotropies in the microwave region and/ormillimetre wave region. The birefringence is, for example, preferably0.14 or more, particularly preferably 0.15 or more, particularlypreferably 0.20 or more, particularly preferably 0.25 or more and veryparticularly preferably 0.30 or more, at about 8.3 GHz. In addition, thebirefringence is preferably 0.80 or less.

The dielectric anisotropy in the microwave region is defined as

Δ∈_(r)≡(∈_(r,∥)−∈_(r,⊥)).

The tuneability (τ) is defined as

τ≡(Δ∈_(r)/∈_(r,∥)).

The material quality (II) is defined as

η≡(τ/tan δ_(∈r,max)), where

the maximum dielectric loss is

tan δ_(∈r,max)≡max. {tan δ_(∈r,⊥,); tan δ_(∈r,∥)}.

The material quality (η) of the preferred liquid-crystal materials is 6or more, preferably 8 or more, preferably 10 or more, preferably 15 ormore, preferably 17 or more, preferably 20 or more, particularlypreferably 25 or more, very particularly preferably 30 and in particular40 or more or even 50 or more.

In the corresponding components, the preferred liquid-crystal materialshave phase shifter qualities of 15°/dB or more, preferably 20°/dB ormore, preferably 30°/dB or more, preferably 40°/dB or more, preferably50°/dB or more, particularly preferably 80°/dB or more and veryparticularly preferably 100°/dB or more.

In some embodiments, however, it is also possible to use liquid crystalshaving a negative value of the dielectric anisotropy.

The liquid crystals employed are either individual substances ormixtures. They preferably have a nematic phase.

The term “alkyl” preferably encompasses straight-chain and branchedalkyl groups, as well as cycloalkyl groups, each having 1 to 15 carbonatoms, in particular the straight-chain groups methyl, ethyl, propyl,butyl, pentyl, hexyl and heptyl, as well as cyclopropyl and cyclohexyl.Groups having 2 to 10 carbon atoms are generally preferred.

The term “alkenyl” preferably encompasses straight-chain and branchedalkenyl groups having 2 to 15 carbon atoms, in particular thestraight-chain groups. Particularly preferred alkenyl groups are C₂- toC₇-1E-alkenyl, C₄- to C₇-3E-alkenyl, C₅- to C₇-4-alkenyl, C₆- toC₇-5-alkenyl and C₇-6-alkenyl, in particular C₂- to C₇-1E-alkenyl, C₄-to C₇-3E-alkenyl and C₅- to C₇-4-alkenyl. Examples of further preferredalkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl,1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl,3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl,6-heptenyl and the like. Groups having up to 5 carbon atoms aregenerally preferred.

The term “fluoroalkyl” preferably encompasses straight-chain groupshaving a terminal fluorine, i.e. fluoromethyl, 2-fluoroethyl,3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and7-fluoroheptyl. However, other positions of the fluorine are notexcluded.

The term “oxaalkyl” or “alkoxyalkyl” preferably encompassesstraight-chain radicals of the formula C_(n)H_(2n+1)—O—(CH₂)_(m), inwhich n and m each, independently of one another, denote an integer from1 to 10. Preferably, n here is 1 and m is 1 to 6.

Compounds containing a vinyl end group and compounds containing a methylend group have low rotational viscosity.

In the present application, both high-frequency technology andhyperfrequency technology denote applications having frequencies in therange from 1 MHz to 100 THz, preferably from 1 GHz to 30 THz, morepreferably 2 GHz to 10 THz, particularly preferably from about 5 GHz to5 THz.

The liquid-crystal media in accordance with the present invention maycomprise further additives and chiral dopants in the usualconcentrations. The total concentration of these further constituents isin the range from 0% to 10%, preferably 0.1% to 6%, based on the mixtureas a whole. The concentrations of the individual compounds used are eachpreferably in the range from 0.1% to 3%. The concentration of these andsimilar additives is not taken into consideration when quoting thevalues and concentration ranges of the liquid-crystal components andliquid-crystal compounds of the liquid-crystal media in thisapplication.

The liquid-crystal media according to the invention consist of aplurality of compounds, preferably 3 to 30, more preferably 4 to 20 andvery preferably 4 to 15 compounds. These compounds are mixed in aconventional manner. In general, the desired amount of the compound usedin the smaller amount is dissolved in the compound used in the largeramount. If the temperature is above the clearing point of the compoundused in the higher concentration, it is particularly easy to observecompletion of the dissolution process. It is, however, also possible toprepare the media in other conventional ways, for example usingso-called pre-mixes, which can be, for example, homologous or eutecticmixtures of compounds, or using so-called “multibottle” systems, theconstituents of which are themselves ready-to-use mixtures.

All temperatures, such as, for example, the melting point T(C,N) orT(C,S), the transition from the smectic (S) to the nematic (N) phaseT(S,N) and the clearing point T(N,I) of the liquid crystals, are quotedin degrees Celsius. All temperature differences are quoted indifferential degrees.

In the present invention and especially in the following examples, thestructures of the mesogenic compounds are indicated by means ofabbreviations, also referred to as acronyms. In these acronyms, thechemical formulae are abbreviated as follows using Tables A to C below.All groups C_(n)H_(2n+1), C_(m)H_(2m+1) and C_(l)H_(2l+1) orC_(n)H_(2n−1), C_(m)H_(2m−1) and C_(l)H_(2l−1) denote straight-chainalkyl or alkenyl, preferably 1E-alkenyl, having n, m and 1 C atomsrespectively, where n, m and 1, independently of one another, denote aninteger from 1 to 9, preferably 1 to 7, or from 2 to 9, preferably 2 to7, respectively. C_(o)H_(2o+1) denotes straight-chain alkyl having 1 to7, preferably 1 to 4, C atoms, or branched alkyl having 1 to 7,preferably 1 to 4, C atoms.

Table A lists the codes used for the ring elements of the corestructures of the compounds, while Table B shows the linking groups.Table C gives the meanings of the codes for the left-hand or right-handend groups. Table D shows illustrative structures of compounds withtheir respective abbreviations.

TABLE A Ring elements C

P

D

DI

A

AI

G

GI

U

UI

Y

fX

fXI

M

MI

N

NI

fN

fNI

dH

N(2, 6)

N(1, 4)

N3f

N3fI

tH

tHI

tH2f

tH2fI

K

KI

L

LI

F

FI

P(o)

PI(o)

P(i3)

PI(c3)

P(t4)

PI(t4)

P(c3)

PI(c3)

P(c4)

PI(c4)

P(c5)

PI(c5)

P(e5)

PI(e5)

P(c6)

PI(c6)

P(e6)

PI(e6)

GI(o)

G(o)

GI(i3)

G(i3)

GI(t4)

G(t4)

GI(c3)

G(c3)

GI(c4)

G(c4)

GI(c5)

G(c5)

GI(e5)

G(e5)

GI(c6)

G(c6)

GI(e6)

G(e6)

TABLE B Linking groups E —CH₂CH₂— Z —CO—O— V —CH═CH— ZI —O—CO— X —CF═CH—O —CH₂—O— XI —CH═CF— OI —O—CH₂— B —CF═CF— Q —CF₂—O— T —C≡C— QI —O—CF₂— W—CF₂CF₂—

TABLE C End groups Left-hand side Right-hand side Use alone -n-C_(n)H_(2n + 1)— -n —C_(n)H_(2n + 1) —nO— C_(n)H_(2n + 1)—O— —nO—O—C_(n)H_(2n + 1) —V— CH₂═CH— —V —CH═CH₂ —nV— C_(n)H_(2n + 1)—CH═CH——nV —C_(n)H_(2n)—CH═CH₂ —Vn— CH₂═CH—C_(n)H_(2n + 1)— —Vn—CH═CH—C_(n)H_(2n + 1) —nVm— C_(n)H_(2n + 1)—CH═CH—C_(m)H_(2m)— —nVm—C_(n)H_(2n)—CH═CH—C_(m)H_(2m + 1) —N— N≡C— —N —C≡N —S— S═C═N— —S —N═C═S—F— F— —F —F —CL— Cl— —CL —Cl —M— CFH₂— —M —CFH₂ —D— CF₂H— —D —CF₂H —T—CF₃— —T —CF₃ —MO— CFH₂O— —OM —OCFH₂ —DO— CF₂HO— —OD —OCF₂H —TO— CF₃O——OT —OCF₃ —OXF— CF₂═CH—O— —OXF —O—CH═CF₂ —A— H—C≡C— —A —C≡C—H —nA—C_(n)H_(2n + 1)—C≡C— —An —C≡C—C_(n)H_(2n + 1) —NA— N≡C—C≡C— —AN —C≡C—C≡NUse together with others - . . . A . . . - —C≡C— - . . . A . . . —C≡C— -. . . V . . . - CH═CH— - . . . V . . . —CH═CH— - . . . Z . . . -—CO—O— - . . . Z . . . —CO—O— - . . . ZI . . . - —O—CO— - . . . ZI . . .—O—CO— - . . . K . . . - —CO— - . . . K . . . —CO— - . . . W . . . -—CF═CF— - . . . W . . . —CF═CF—in which n and m each denote integers, and the three dots “ . . . ” areplaceholders for other abbreviations from this table.

The following table shows illustrative structures together with theirrespective abbreviations. These are shown in order to illustrate themeaning of the rules for the abbreviations. They furthermore representcompounds which are preferably used.

TABLE D Illustrative structures The illustrative structures showcompounds which are particularly preferably employed. Examples ofcompounds of component A

Examples of compounds of component B

Examples of compounds of component C

Examples of compounds of component E Compounds having three 6-memberedrings

Compounds having four 6-membered rings

Illustrative structures of polar compounds employed:

Illustrative structures of further neutral compounds preferablyemployed:

Illustrative structures of further polar compounds employed:

The following table, Table E, shows illustrative compounds which can beused as stabiliser in the mesogenic media in accordance with the presentinvention. The total concentration of these and similar compounds in themedia is preferably 5% or less.

TABLE E

In a preferred embodiment of the present invention, the mesogenic mediacomprise one or more compounds selected from the group of the compoundsfrom Table E.

The following table, Table F, shows illustrative compounds which canpreferably be used as chiral dopants in the mesogenic media inaccordance with the present invention.

TABLE F

In a preferred embodiment of the present invention, the mesogenic mediacomprise one or more compounds selected from the group of the compoundsfrom Table F.

The mesogenic media in accordance with the present applicationpreferably comprise two or more, preferably four or more, compoundsselected from the group consisting of the compounds from the abovetables.

The liquid-crystal media in accordance with the present inventionpreferably comprise

-   -   seven or more, preferably eight or more, compounds, preferably        compounds having three or more, preferably four or more,        different formulae, selected from the group of the compounds        from Table D.

EXAMPLES

The following examples illustrate the present invention without limitingit in any way. However, it becomes clear to the person skilled in theart from the physical properties what properties can be achieved and inwhat ranges they can be modified. In particular, the combination of thevarious properties which can preferably be achieved is thus well definedfor the person skilled in the art.

The acetylenes employed, if not commercially available, are synthesisedin accordance with standard laboratory procedures.

Example compounds of the formula I for component A

Substance Example 1

Phase sequence: C 87° C. N 178.5° C. I; Δn=0.436; Δ∈=2.8.

Substance Example 2

Phase sequence: C 78° C. N 172.3° C. I; Δn=0.437; Δ∈=2.6.

Substance Example 3

Phase sequence: C 107° C. N 211.0° C. I; Δn=0.464; Δ∈=3.1.

Substance Example 4

Phase sequence: C 87° C. N 130.7° C. I; Δn=0.451; Δ∈=2.1.

Substance Example 5

Phase sequence: C 57° C. N 151.7° C. I; Δn=0.445; Δ∈=2.0.

Substance Example 6

Phase sequence: C 29° C. N 119.2° C. I; Δn=0.402; Δ∈=1.7.

Substance Example 7

Phase sequence: T_(g) −54° C. C 14° C. N 119.2° C. I; Δn=0.393; Δ∈=1.8.

Substance Example 8

Phase sequence: C 60° C. N 121.8° C. I; Δn=0.394; Δ∈=1.7.

Substance Example 9

Phase sequence: C 81° C. N 160.7° C. I; Δn=0.432; Δ∈=3.2.

Substance Example 10

Synthesis Example 10:1,4-Bis(2-(4-butylphenyl)ethynyl)-2-cyclopropylbenzene 10.1)1,4-Dichloro-2-cyclopropylbenzene 2

20 g (73 mmol) of 1,4-dichloro-2-iodobenzene, 9.4 g (110 mmol) ofcyclopropylboronic acid, 32 g (147 mmol) of potassium phosphate, 421 mg(0.7 mmol) of bis(dibenzylideneacetone)palladium(0) (Pd(dba)₂) and 1096mg (1.5 mmol) of 1,2,3,4,5-pentaphenyl-1-(di-t-butylphosphine)ferrocene(CTC-Q-PHOS) are dissolved in 600 ml of toluene and heated at 100° C.overnight. 100 ml of water are added to the cooled solution, and themixture is extracted twice with toluene (100 ml). The combined organicphases are washed with water, dried over sodium sulfate and evaporatedin vacuo. The residue is purified by column chromatography, giving thetitle compound as a colourless solid.

10.2) 1,4-Bis(2-(4-butylphenyl)ethynyl)-2-cyclopropylbenzene (1)

5 g (26 mmol) of 1,4-dichloro-2-cyclopropylbenzene, 9.4 g (58 mmol) of1-n-butyl-4-ethynylbenzene, 19 g (58 mmol) of caesium carbonate, 69 mg(0.3 mmol) of bis(acetonitrile)palladium(II) chloride and 382 mg (0.8mmol) of 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl aredissolved in 80 ml of dioxane under nitrogen, and the mixture is heatedat 100° C. overnight. 100 ml of water are added to the cooled solution,and the mixture is extracted twice with methyl t-butyl ether (100 ml).The combined organic phases are washed with water, dried over sodiumsulfate and evaporated in vacuo. The residue is purified by columnchromatography and recrystallised from ethanol, giving the titlecompound 1 as a solid.

¹H-NMR (250 MHz, CDCl₃): 7.4-7.08 (11H, m); 2.5 (4H, m); 1.6-1.3 (9H,m); 0.96 (6H, m); 0.6-0.4 (4H, m).

Phase sequence: C 72° C. N 84.5° C. I; Δn=0.378; Δ∈=1.5.

Substance Example 12

Phase sequence: T_(g) −43° C. C 46° C. N 86.0° C. I; Δn=0.379; Δ∈=1.1.

Substance Example 13

Synthesis Example 13:1,4-Bis(2-(4-butylphenyl)ethynyl)-2-cyclobutylbenzene 3

13.1) 1-(2,5-Dibromophenyl)cyclobutanol 4

21.09 g (67 mmol) of 1,2,4-tribromobenzene are initially introduced in100 ml of THF under nitrogen, cooled to −45° C., and a solution (1.3 M)of 51.54 ml (67 mmol) of isopropylmagnesium chloride/lithium chloridecomplex in THF is added dropwise. After 1 hour, the batch is warmed to−10° C., and 5 ml (66.34 ml) of cyclobutanone are added dropwise at thistemperature. The batch is allowed to thaw, and sat. NH₄Cl solution isadded, the mixture is extracted with methyl t-butyl ether, the organicphase is dried over sodium sulfate and filtered, the solvent is removedin vacuo, and the residue is filtered through silica gel withdichloromethane, giving 4, which is employed in the next step withoutfurther purification.

13.2) 1,4-Dibromo-2-cyclobutylbenzene 5

14.5 g (47.39 mmol) of 4 are dissolved in 50 ml of THF under nitrogen,and 35.72 ml (284.4 mmol) of boron trifluoride/diethyl ether complex areadded dropwise at room temperature, and 12.54 g (189.6 mmol) of sodiumcyanoborohydride are added dropwise in portions. The batch is heatedunder reflux overnight. The batch is allowed to cool to roomtemperature, sat. NaHCO₃ solution is added, the mixture is extractedwith methyl t-butyl ether, the organic phase is dried over sodiumsulfate and filtered, the solvent is removed in vacuo, and the residueis filtered through silica gel with 1-chlorobutane, giving 5 as a yellowliquid.

13.3) 1,4-Bis(2-(4-butylphenyl)ethynyl)-2-cyclobutylbenzene 3

7.8 g (47.0 mmol) of 1-butyl-4-ethynylbenzene are initially introducedin 100 ml of THF under nitrogen, cooled to −78° C., and 63.32 ml (63.20mmol) of a 1 M solution of lithium bis(trimethylsilyl)amide in hexaneare added dropwise. After 1 hour, 63.22 ml (63.20 mmol) of a 1 Msolution of 9-methoxy-9-BBN in hexane are added, and the mixture is leftto stir at −78° C. for 2 hours. In a second apparatus, 6.8 g (23.45mmol) of 5, 0.916 g (1.0 mmol) oftris-(dibenzylideneacetone)dipalladium(0) and 1.64 g (4.0 mmol) of2-dicyclo-hexylphosphino-2′,6′-dimethoxybiphenyl in 100 ml of THF areinitially introduced. The first solution is slowly added dropwise, andthe batch is heated at 100° C. overnight. 100 ml of water are added tothe cooled solution, and the mixture is extracted twice with methylt-butyl ether (100 ml). The combined organic phases are washed withwater, dried over sodium sulfate and evaporated in vacuo. The residue ispurified by column chromatography and recrystallised from isopropanol,giving the title compound 3 as a solid.

Phase sequence: T_(g) −39° C. C 69° C. N 70.1° C. I; Δn=0.359; Δ∈=0.9.

Substance Example 14

Phase sequence: T_(g) −36° C. C 57° C. N(?) (7.0)° C. I; Δn=0.334;Δ∈=−0.1.

Substance Example 15

Phase sequence: T_(g) −34° C. C 47° C. N 53.1° C. I; Δn=0.337; Δ∈=0.0.

Substance Example 16

Synthesis Example 16:2-Cyclohexyl-4-(4-hexylphenylethynyl)-1-(4-propylphenylethynyl)-benzene6 16.1) 4-Chloro-2-cyclohexylbenzene trifluoromethanesulfonate 7

19 g (90.2 mmol) of 4-chloro-2-cyclohexylbenzene are dissolved in 264 mlof dichloromethane, cooled to −5° C., and 4.64 ml (33.18 mmol) oftriethylamine and 223 mg (1.8 mmol) of 4-(dimethylamino)pyridine areadded dropwise. The batch is stirred at room temperature overnight andfiltered through silica gel with dichloromethane, giving the product 7,which is employed in the next step without further purification.

16.2) (4-Chloro-2-cyclohexylphenylethynyl)trimethylsilane 8

21 g (61.3 mmol) of 7, 25.8 ml (183.8 mmol) of trimethylsilylacetylene,2.15 g (3 mmol) of bis(triphenylphosphine)palladium(II) chloride and21.2 ml (153.2 mmol) of triethylamine are dissolved in 60 ml ofN,N-dimethylformamide under nitrogen, and the mixture is heated at 100°C. overnight. 100 ml of water are added to the cooled solution, and themixture is extracted twice with methyl t-butyl ether (100 ml). Thecombined organic phases are washed with water, dried over sodium sulfateand evaporated in vacuo. The residue is purified by columnchromatography, giving the product 8, which is employed in the next stepwithout further purification.

16.3) 4-Chloro-2-cyclohexyl-1-ethynylbenzene 9

16.6 g (57.1 mmol) of 8 are dissolved in 154 ml of tetrahydrofuran,cooled to 0° C., and a 1 M solution of tetra-n-butylammonium fluoride(68.48 mmol) is added dropwise. The batch is stirred at room temperatureovernight, water is added, the mixture is extracted with methyl t-butylether, the organic phase is dried over sodium sulfate and filtered, thesolvent is removed in vacuo, and the residue is filtered through silicagel with heptane/toluene, giving the product 9, which is employed in thenext step without further purification.

16.4) 4-Chloro-2-cyclohexyl-1-p-tolylethynylbenzene 10

6.6 g (30.17 mmol) of 9, 7.28 g (30.17 mmol) of 1-bromo-4-hexylbenzene,21.63 g (66.39 mmol) of caesium carbonate, 78 mg (0.3 mmol) ofbis(acetonitrile)palladium(II) chloride and 431 mg (0.9 mmol) of2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl are dissolved in90 ml of dioxane under nitrogen and heated at 100° C. overnight. 100 mlof water are added to the cooled solution, and the mixture is extractedtwice with methyl t-butyl ether (100 ml). The combined organic phasesare washed with water, dried over sodium sulfate and evaporated invacuo. The residue is purified by column chromatography.

16.5)2-Cyclohexyl-4-(4-hexylphenylethynyl)-1-(4-propylphenylethynyl)benzene 6

4.5 g (11.87 mmol) of 10, 1.7 g (11.87 mmol) of1-n-propyl-4-ethynylbenzene, 8.5 g (26.12 mmol) of caesium carbonate, 30mg (0.1 mmol) of bis(acetonitrile)-palladium(II) chloride and 170 mg(0.35 mmol) of 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl aredissolved in 35 ml of dioxane under nitrogen and heated at 100° C.overnight. 100 ml of water are added to the cooled solution, and themixture is extracted twice with methyl t-butyl ether (100 ml). Thecombined organic phases are washed with water, dried over sodium sulfateand evaporated in vacuo. The residue is purified by columnchromatography, giving the title compound 6 as a solid.

Phase sequence: T_(g) −23° C. I; Δn=0.294; Δ∈=−0.6.

Substance Example 17

The compound is prepared analogously to Example 11.

Phase sequence: C 90° C. N 193.9° C. I; Δn=0.435; Δ∈=3.0.

Substance Example 18

The compound is prepared analogously to Example 11.

Phase sequence: C 53° C. N 143.5° C. I; Δn=0.401; Δ∈=2.5.

Substance Example 19

The compound is prepared analogously to Example 11.

Phase sequence: T_(g) −49 C 32° C. N 126.0° C. I; Δn=0.373; Δ∈=1.6.

Substance Example 20

Substance Example 21

Phase sequence: T_(g) −45° C. C 60° C. N 89.1° C. I; Δn=0.348; Δ∈=1.3.

Substance Example 22

Phase sequence: T_(g) −32° C. C 66° C. N (44.1)° C. I; Δn=0.322; Δ∈=0.6.

Substance Example 23

Phase sequence: T_(g) −37° C. C 52° C. N 78.2° C. I; Δn=0.339; Δ∈=0.9.

Synthesis Example 24

Step 24.1

25.4 g of 2-bromo-1,4-dichlorobenzene, 8.9 ml of iodoethane and 13.3 mlof DMPU are dissolved in 230 ml of THF, and a solution of 16.2 g oflithium tetra-methylpiperidite in THF is added dropwise at −70° C. Aftera further 2 h at −70° C., the reaction mixture is allowed to warm toambient temperature, and the batch is hydrolysed using water andsubjected to extractive work-up. The crude product is purified byfractional distillation.

B.p.: 73° C./0.1 bar. Colourless liquid.

Step 24.2

12.5 ml of a 5% solution of methyllithium in diethyl ether are added to2.4 g of anhydrous zinc bromide in 50 ml of THF at 25-40° C. 0.3 g ofPdCl₂-dppf, bis-(diphenylphosphinoferrocene)palladium dichloride, isthen added, the mixture is heated to the boil, and 4.6 g of the productfrom step 1.1, dissolved in a little THF, are added dropwise. Thereaction mixture is subsequently heated under reflux for 15 h. The batchis hydrolysed using water and subjected to extractive work-up.

The crude product is purified by chromatography (pentane/silica gel).Colourless liquid.

Step 24.3

2.4 g of 4-butylphenylacetylene are initially introduced in 30 ml of THFand cooled to −78° C. 14.3 ml of a 1 M solution of lithiumbis(trimethylsilyl)amide in hexane are added dropwise to this solutionand allowed to react at −78° C. for a further 1 h. 14.3 ml of a 1 Msolution of methoxy-9-BBN are then added dropwise, and the mixture isstirred at −78° C. for a further 2 h. In a second apparatus, 1.0 g ofthe product from the last step, dissolved in 40 ml of THF, is initiallyintroduced with the catalyst comprising 0.2 g oftris(dibenzylideneacetone)dipalladium and 0.35 g of2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl, and the reactionsolution from the first reaction is added at room temperature. Themixture is heated at the boil for 15 h. The batch is hydrolysed usingwater and subjected to extractive work-up. The crude product is purifiedby chromatography (pentane/silica gel). Recrystallisation from pentanegives the purified title product.

Phase sequence: C 45 N 1801.

Substance Example 25

The compound is prepared analogously to Example 24.

Phase sequence: C 118 N 222 I; Δn=0.435; Δ∈=2.6.

Substance Example 26

The title compound is prepared analogously to Example 24.

Phase sequence: C 41 N 161 I.

Substance Example 27

Synthesis Example 27 27.1) Synthesis of 1-iodo-4-bromonaphthalene

100 g (350 mmol) of 1,4-dibromonaphthalene are initially introduced in 1l of THF, cooled to −70° C., and 235 ml of n-BuLi (1.6 M in hexane, 370mmol) are added dropwise. After 1 h, 103 g (406 mmol) of I₂ in 250 ml ofTHF are added dropwise, the mixture is stirred at −70° C. for a further2 h, warmed to 0° C. and quenched by the addition of 50 ml (644 mmol) ofaqueous NaHSO₃ solution (w=39%). The phases are separated, and theaqueous phase is extracted once with MTB. The combined organic phasesare washed with saturated sodium chloride soln., dried over sodiumsulfate, filtered and evaporated in a rotary evaporator. The residue ispurified by column chromatography (SiO₂, heptane), and the furtherpurification is carried out by recrystallisation from isopropanol,giving 1-iodo-4-bromonaphthalene as a yellow solid.

27.2) Synthesis of 1-bromo-4-(4-n-propylphenylethynyl)naphthalene

15.3 g (43.6 mmol) of 1-iodo-4-bromonaphthalene and 7.25 g (5.3 mmol) of4-n-propylphenylacetylene are initially introduced in 200 ml of NEt₃,170 mg (0.9 mmol) of copper(I) iodide and 600 mg (0.9 mmol) ofbis(triphenylphosphine)palladium(II) chloride are added, and the mixtureis refluxed for 30 minutes. The batch is cooled, water and heptane areadded, and the phases are separated. The organic phase is washed withsaturated sodium chloride soln., dried over sodium sulfate, filtered andevaporated in a rotary evaporator. The residue is purified by columnchromatography (SiO₂, heptane), and the further purification is carriedout by recrystallisation from isopropanol.

27.3) Synthesis of1-(4-n-butylphenylethynyl)-4-(4-n-propylphenylethynyl)-naphthalene

2.35 g (6.3 mmol) of 1-bromo-4-(4-n-propylphenylethynyl)naphthalene and1.33 g (8.4 mmol) of 4-n-butylphenylacetylene are initially introducedin 40 ml of NEt₃, 60 mg (0.3 mmol) of copper(I) iodide and 200 mg (0.3mmol) of bis-(triphenylphosphine)palladium(II) chloride are added, andthe mixture is refluxed for 18 h.

The batch is cooled, water and heptane are added, and the phases areseparated. The organic phase is washed with saturated ammonium chloridesolution and subsequently with saturated sodium chloride soln., driedover sodium sulfate, filtered and evaporated in a rotary evaporator. Theresidue of compound (I) is purified by column chromatography (SiO₂,heptane), and the further purification is carried out byrecrystallisation from isopropanol.

MS (O): m/e (%)=426 (100, M⁺), 397 (11, [M−ethyl]⁺), 383 (16,[M−propyl]⁺), 354 (18, [M−ethylpropyl]⁺), 177 (14, [M−ethylpropyl]²⁺).

Phase sequence: C 78 N 1911; Δn=0.450; Δ∈=2.9.

Substance Example 28

The compound is prepared analogously to Example 27.

Phase sequence: C 108° C. N 194° C. I.

Substance Example 29

The compound is prepared analogously to Example 27.

Phase sequence: C 63° C. N 171.7° C. I; Δn=0.435; Δ∈=2.3.

Substance Example 30

The compound is prepared analogously to Example 27.

Phase sequence: C 76° C. N 176.2° C. I; Δn=0.427; Δ∈=2.4.

Substance Example 31

The compound is prepared analogously to Example 27.

Phase sequence: C 100° C. N 162° C. I.

Substance Example 32

The compound is prepared analogously to Example 27.

Phase sequence: C 61° C. N 139° C. I.

Substance Example 33

This compound is prepared analogously to the preceding compounds inaccordance with the right-hand reaction path of Scheme 13.

Phase sequence: C 85° C. N 202.4° C. I; Δn=0.446; Δ∈=2.0.

Substance Example 34

The compound is prepared analogously to Example 33.

Phase sequence: C 112° C. N 253.5° C. I; Δn=0.484; Δ∈=4.1.

Substance Example 35

This compound is prepared analogously to the preceding compounds inaccordance with the left-hand reaction path of Scheme 13.

Phase sequence: C 93° C. N 212.4° C. I; Δn=0.527; Δ∈=0.8.

USE EXAMPLES Comparative Example 1

A liquid-crystalline substance having the abbreviation PTP(2)TP-6-3 isprepared by the method of Hsu, C. S., Shyu, K. F., Chuang, Y. Y. and Wu,S.-T., Liq. Cryst., 27 (2), (2000), pp. 283-287, and investigated withrespect to its physical properties, in particular in the microwaveregion. The compound has a nematic phase and a clearing point (T(N,I))of 114.5° C. Further physical properties at 20° C. are: n_(e)(589.3nm)=1.8563; Δn(589.3 nm)=0.3250; ∈_(∥) (1 kHz), 4.3; Δ∈(1 kHz)=1.8 andγ₁=2.100 mPa·s. The compound is suitable for applications in themicrowave region and/or millimetre wave region, in particular for phaseshifters.

TABLE 1 Properties of the compound PTP(2)TP-6-3 at 19 GHz T/° C.ε_(r,||) ε_(r,⊥) τ tan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 3.35 2.42 0.2780.0029 0.0061 45.2

TABLE 2 Comparison of the properties of the various examples at 19 GHzand 20° C. Example LC ε_(r,||) ε_(r,⊥) τ tan δ_(ε max.) η ComparisonP2-6-3* 3.35 2.42 0.278 0.0061 45.2 1 M-1 3.41 2.47 0.275 0.0059 46.4 2M-2 3.44 2.47 0.280 0.0070 40.1 3 M-3 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d.4 M-4 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d. 5 M-5 3.50 2.48 0.290 0.004466   6 M-6 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d. 7 M-7 t.b.d. t.b.d. t.b.d.t.b.d. t.b.d. 8 M-8 3.38 2.42 0.285 0.0057 50.4 9 M-9 3.34 2.41 0.2770.0060 46.4 10  M-10 3.34 2.40 0.281 0.0060 46.7 11  M-11 t.b.d. t.b.d.t.b.d. t.b.d. t.b.d. 12  M-12 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d. Notes:*P2-6-3: PTP(2)TP-6-3, LC: liquid crystal and t.b.d.: to be determined.

Example 1

A liquid-crystal mixture M-1 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTGI(c3)TP-4-4 40.0 2PTGI(c4)TP-4-4 20.0 3 PTN(1,4)TP-4-4 15.0 4 PTN(1,4)TP-3-6 25.0 Σ 100.0Physical properties T(N,I) = 136.5 ° C. n_(e) (20° C., 589.3 nm) = 1.553Δn (20° C., 589.3 nm) = 0.408 ε_(∥) (20° C., 1 kHz) = 3.7 Δε (20° C., 1kHz) = 0.9 k₁₁ (20° C.) = 11.3 pN k₃₃/k₁₁ (20° C.) = 3.88 V₀ (20° C.) =3.71 V γ₁ (20° C.) = 2.903 mPa · s

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 3 Properties of mixture M-1 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 3.41 2.47 0.275 0.0026 0.0059 46.4

Example 2

A liquid-crystal mixture M-2 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTGI(c3)TP-4-4 40.0 2 PPTUI-3-420.0 3 PTN(1,4)TP-4-4 15.0 4 PTN(1,4)TP-3-6 25.0 Σ 100.0 Physicalproperties T(N,I) = 150 ° C. n_(e) (20° C., 589.3 nm) = 1.548 Δn (20°C., 589.3 nm) = 0.41 ε_(∥) (20° C., 1 kHz) = 3.7 Δε (20° C., 1 kHz) =1.0 k₁₁ (20° C.) = 13.6 pN k₃₃/k₁₁ (20° C.) = 3.17 V₀ (20° C.) = 3.93 Vγ₁ (20° C.) = 2.114 mPa · s

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 4 Properties of mixture M-2 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 3.44 2.47 0.280 0.0023 0.0070 40.1

Example 3

A liquid-crystal mixture M-3 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTP(c3)TP-4-4 10.0 2PTP(c3)TP-6-3 20.0 3 PTP(c4)TP-4-4 15.0 4 PTGI(c4)TP-4-4 15.0 5PTGI(e5)TP-4-4 20.0 6 PTPI(2)PP(2)-4-4 10.0 7 PTPI(2)P(2)TP-4-4 10.0 Σ100.0 Physical properties T(N,I) = 104 ° C. n_(e) (20° C., 589.3 nm) =t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥) (20° C., 1 kHz) = t.b.d. Δε(20° C., 1 kHz) = 1.0 k₁₁ (20° C.) = t.b.d. pN k₃₃/k₁₁ (20° C.) = t.b.d.V₀ (20° C.) = t.b.d. V γ₁ (20° C.) = t.b.d. mPa · s Note: t.b.d.: to bedetermined.

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 5 Properties of mixture M-3 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d.t.b.d. Note: t.b.d.: to be determined.

Example 4

A liquid-crystal mixture M-4 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTPI(2)TP(2)TP-4-4 10.0 2GGP-3-CL 10.0 3 GGP-5-CL 20.0 4 PPTUI-3-2 20.0 5 PPTUI-3-4 20.0 6PPTUI-4-4 20.0 Σ 100.0 Physical properties T(N,I) = 153 ° C. n_(e) (20 °C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥) (20° C., 1kHz) = 7.7 Δε (20° C., 1 kHz) = 4.4 k₁₁ (20° C.) = 16.6 pN k₃₃ (20° C.)= 34.5 pN V₀ (20° C.) = 2.06 V γ₁ (20° C.) = 874 mPa · s Note: t.b.d.:to be determined.

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 6 Properties of mixture M-4 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d.t.b.d. Note: t.b.d.: to be determined.

Example 5

A liquid-crystal mixture M-5 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTN(1,4)TP-3-3 5.0 2PTN(1,4)TP-5-5 5.0 3 PTN(1,4)TP-4-4 30.0 4 PTN(1,4)TP-6-6 30.0 5PTN(1,4)TP-3-6 30.0 Σ 100.0 Physical properties T(N,I) = 166.5 ° C.n_(e) (20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥)(20° C., 1 kHz) = 3.5 Δε (20° C., 1 kHz) = 0.9 k₁₁ (20° C.) = 17.2 pNk₃₃ (20° C.) = 31.4 pN V₀ (20° C.) = 4.6 V γ₁ (20° C.) = t.b.d. mPa · sNote: t.b.d.: to be determined.

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 7 Properties of mixture M-5 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 3.50 2.48 0.290 0.0017 0.0044 66

Example 6

A liquid-crystal mixture M-6 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTPI(2)P(2)TP-4-4 10.0 2PTP(2)TP-6-3 90.0 Σ 100.0 Physical properties T(N,I) = 125.5 ° C. n_(e)(20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥) (20°C., 1 kHz) = 3.4 Δε (20° C., 1 kHz) = 0.9 k₁₁ (20° C.) = 12.7 pN k₃₃/k₁₁(20° C.) = 4.1 V₀ (20° C.) = 4.08 V γ₁ (20° C.) = t.b.d. mPa · s Note:t.b.d.: to be determined.

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 8 Properties of mixture M-6 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d.t.b.d. Note: t.b.d.: to be determined.

Example 7

A liquid-crystal mixture M-7 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTPP(2)TP-4-4 10.0 2PTP(2)TP-6-3 90.0 Σ 100.0 Physical properties T(N,I) = 125.5 ° C. n_(e)(20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥) (20°C., 1 kHz) = 3.4 Δε (20° C., 1 kHz) = 0.9 k₁₁ (20° C.) = 13.0 pN k₃₃/k₁₁(20° C.) = 4.7 V₀ (20° C.) = 4.10 V γ₁ (20° C.) = t.b.d. mPa · s Note:t.b.d.: to be determined.

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 9 Properties of mixture M-7 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d.t.b.d. Note: t.b.d.: to be determined.

Example 8

A liquid-crystal mixture M-8 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTPI(2)TP(2)TP-4-4 10.0 2PTP(2)TP-6-3 90.0 Σ 100.0 Physical properties T(N,I) = 127 ° C. n_(e)(20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥) (20°C., 1 kHz) = 3.4 Δε (20° C., 1 kHz) = 0.9 k₁₁ (20° C.) = 13.3 pN k₃₃/k₁₁(20° C.) = 3.8 V₀ (20° C.) = 4.14 V γ₁ (20° C.) = t.b.d. mPa · s Note:t.b.d.: to be determined.

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 10 Properties of mixture M-8 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 3.38 2.42 0.285 0.0024 0.0057 50.4

Example 9

A liquid-crystal mixture M-9 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTP(c3)TP-4-4 10.0 2PTP(2)TP-6-3 90.0 Σ 100.0 Physical properties T(N,I) = 116 ° C. n_(e)(20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥) (20°C., 1 kHz) = t.b.d. Δε (20° C., 1 kHz) = t.b.d. k₁₁ (20° C.) = t.b.d. pNk₃₃/k₁₁ (20° C.) = t.b.d. V₀ (20° C.) = t.b.d. V γ₁ (20° C.) = t.b.d.mPa · s Note: t.b.d.: to be determined.

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 11 Properties of mixture M-9 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 3.34 2.41 0.277 0.0025 0.0060 46.4

Example 10

A liquid-crystal mixture M-10 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTGI(c3)TP-4-4 10.0 2PTP(2)TP-6-3 90.0 Σ 100.0 Physical properties T(N,I) = 120 ° C. n_(e)(20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥) (20°C., 1 kHz) = t.b.d. Δε (20° C., 1 kHz) = t.b.d. k₁₁ (20° C.) = t.b.d. pNk₃₃/k₁₁ (20° C.) = t.b.d. V₀ (20° C.) = t.b.d. V γ₁ (20° C.) = t.b.d.mPa · s Note: t.b.d.: to be determined.

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 12 Properties of mixture M-10 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 3.34 2.40 0.281 0.0025 0.0060 46.7

Example 11

A liquid-crystal mixture M-11 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTP(c4)TP-4-4 10.0 2PTP(2)TP-6-3 90.0 Σ 100.0 Physical properties T(N,I) = 114 ° C. n_(e)(20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥) (20°C., 1 kHz) = t.b.d. Δε (20° C., 1 kHz) = t.b.d. k₁₁ (20° C.) = t.b.d. pNk₃₃/k₁₁ (20° C.) = t.b.d. V₀ (20° C.) = t.b.d. V γ₁ (20° C.) = t.b.d.mPa · s Note: t.b.d.: to be determined

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 13 Properties of mixture M-11 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d.t.b.d. Note: t.b.d.: to be determined.

Example 12

A liquid-crystal mixture M-12 having the composition and properties asindicated in the following table is prepared.

Composition Compound No. Abbreviation 1 PTGI(c4)TP-4-4 10.0 2PTP(2)TP-6-3 90.0 Σ 100.0 Physical properties T(N,I) = 117 ° C. n_(e)(20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε_(∥) (20°C., 1 kHz) = t.b.d. Δε (20° C., 1 kHz) = t.b.d. k₁₁ (20° C.) = t.b.d. pNk₃₃/k₁₁ (20° C.) = t.b.d. V₀ (20° C.) = t.b.d. V γ₁ (20° C.) = t.b.d.mPa · s Note: t.b.d.: to be determined.

This mixture is very highly suitable for applications in the microwaveregion and/or millimetre wave region, in particular for phase shifters.

TABLE 14 Properties of mixture M-12 at 19 GHz T/° C. ε_(r,||) ε_(r,⊥) τtan δ_(ε,r,||) tan δ_(ε,r,⊥) η 20 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d.t.b.d. Note: t.b.d.: to be determined.

1. Liquid-crystal medium, characterised in that it comprises a componentA which consists of one or more compounds of the formula I,

in which

denotes

L¹ denotes alkyl having 1 to 6 C atoms, cycloalkyl having 3 to 6 C atomsor cycloalkenyl having 4 to 6 C atoms, X¹ denotes H, alkyl having 1 to 3C atoms or halogen, R¹¹ to R¹⁴, independently of one another, denoteunfluorinated alkyl or unfluorinated alkoxy, each having 1 to 15 Catoms, unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinatedalkoxyalkyl, each having 2 to 15 C atoms, or cycloalkyl,alkylcycloalkyl, cycloalkenyl, alkylcycloalkenyl, alkylcycloalkylalkylor alkylcycloalkenylalkyl, each having up to 15 C atoms, andalternatively one of R¹³ and R¹⁴ or both also denote H. 2.Liquid-crystal medium according to claim 1, characterised in thatcomponent A comprises one or more compounds selected from the group ofthe compounds of the formulae I-1 to I-4

in which the parameters have the meanings given in claim
 1. 3.Liquid-crystal medium according to claim 2, characterised in thatcomponent A comprises one or more compounds of the formula I-2 and/or ofthe formula I-3 and/or of the formula I-4, as indicated in claim
 2. 4.Liquid-crystal medium according to claim 2, characterised in thatcomponent A comprises one or more compounds of the formula I-1, asindicated in claim 2, in which X¹ denotes H.
 5. Liquid-crystal mediumaccording to claim 2, characterised in that component A comprises one ormore compounds of the formula I-1, as indicated in claim 2, in which X¹denotes F.
 6. Liquid-crystal medium according to claim 1, characterisedin that, besides a component A, it additionally comprises one or morecomponents selected from the group of the following components,components B to E: a strongly dielectrically positive component,component B, which has a dielectric anisotropy of 10 or more, a stronglydielectrically negative component, component C, which has a dielectricanisotropy having a value of 5 or more, a component, component D, whichhas a dielectric anisotropy in the range from more than −5.0 to lessthan 10.0 and consists of compounds having seven or more five- orsix-membered rings, and a component, component E, which likewise has adielectric anisotropy in the range from more than −5.0 to less than 10.0and consists of compounds having up to six five- or six-membered rings.7. Liquid-crystal medium according to claim 6, characterised in that itcomprises a component B.
 8. Liquid-crystal medium according to claim 6,characterised in that it comprises a component C.
 9. Liquid-crystalmedium according to claim 6, characterised in that it comprises acomponent D.
 10. Liquid-crystal medium according to claim 1,characterised in that it comprises one or more compounds of the formulaVI

in which L⁶¹ denotes R⁶¹ and, in the case where Z⁶¹ and/or Z⁶² denotetrans-CH═CH— or trans-CF═CF—, alternatively also denotes X⁶¹, L⁶²denotes R⁶² and, in the case where Z⁶¹ and/or Z⁶² denote trans-CH═CH— ortrans-CF═CF—, alternatively also denotes X⁶², R⁶¹ and R⁶², independentlyof one another, denote H, unfluorinated alkyl or unfluorinated alkoxyhaving 1 to 17 C atoms or unfluorinated alkenyl, unfluorinatedalkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, X⁶¹ andX⁶², independently of one another, denote F or Cl, —CN, —NCS, —SF₅,fluorinated alkyl or alkoxy having 1 to 7 C atoms or fluorinatedalkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms, or —NCS, oneof Z⁶¹ and Z⁶² denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and theother, independently thereof, denotes trans-CH═CH—, trans-CF═CF— or asingle bond, and

 to

 independently of one another, denote


11. Process for the preparation of a liquid-crystal medium according toclaim 1, characterised in that one or more compounds of the formula I,as indicated in claim 1, are mixed with one or more further compoundsand/or with one or more additives.
 12. Use of a liquid-crystal mediumaccording to claim 1 in a component for high-frequency technology. 13.Component for high-frequency technology, characterised in that itcontains a liquid-crystal medium according to claim
 1. 14. Microwaveantenna array, characterised in that it comprises one or more componentsaccording to claim
 13. 15. Process for tuning a microwave antenna array,characterised in that a component according to claim 13 is electricallyaddressed.
 16. Compound selected from the group of the compounds of theformulae I-3 and I-4,

in which the parameters have the meanings given in claim
 1. 17. Processfor the preparation of a compound selected from the group of thecompounds of the formulae I-3 and I-4,

in which the parameters have the meanings given in claim
 1. 18. A liquidcrystal mixture comprising a compound selected from the group of thecompounds of the formulae I-3 and I-4 of claim 16.